Materials & Methods
Incubator trays were loaded with approximately 1522 eggs per tray. Water (11 degrees C) flowing over the trays at 8 L per minute was untreated (control), treated with 1667 mg/L of formalin, or treated with 700 mg/L of hydrogen peroxide (H202). All trays were “hand-picked” to eliminate fungal mortality in the control trays. Treatments were continued for twenty days.
The eggs were taken from the hatchery on selected days and transported in a buffer solution. The specimens then underwent inspection using the scanning electron microscope. During low vacuum observations, no additional preparation was necessary. However, for high vacuum observations eggs were dissected in buffer, treated with gluteraldhyde, osmium tetroxide, dehydrated, critical point dried, and coated with gold or gold/palladium. Five randomly selected sampling sites were viewed from three to five eggs for each sampling date, treatment, and incubator tray location. Each sample site was 32.5 x 42.5mm. Eggs were observed at 300x. Each micrograph was reviewed in order to record microbe levels and determine membrane condition.
Data were analyzed using analysis of variance with the SPSSS (9.0) statistical analysis program (SPSS 1999). Pairwise mean comparisons were performed using Fisher’s Protected Least Significance Difference, with significance predetermined at P<0.05 (Ott 1984). All embryo survival percentage data were arcsine transformed prior to analysis to stabilize the variances (Ott 1984).